The operation of low volume oil wells has always been an economical problem and more particularly so today with the increased cost of energy to power the pumping unit. Oil well pumping units can be run by electric motors, diesel or gasoline engines, or a gas-driven engine. An ideal well would be one that produced both oil and gas in sufficient amounts so that the engine running the pumping unit could be driven strictly from the gas. Many stripper wells, which are marginal low-volume wells, must sometimes be shut down and capped because the cost of energy to run the pumping unit exceeds the profit potential of the well. With the current high cost of bottled gas, many of these stripper wells can no longer be operated.
The present invention can be utilized in these marginal stripper wells whereby the oil pumped from the well can be run through a gas extractor whereby the light hydrocarbons can be removed from the crude without substantially affecting the specific gravity of the oil and provide an energy source for powering the pumping unit. These light hydrocarbons would include the gases of ethane, methane, butane, propane and isobutane.
Oil pumping units are basically unattended, and therefore the extractor and its related sources of oil, exhaust gas, air, etc., must be automatically controlled so that the pumping unit continues to operate for long periods of time in the absence of an operator. While this basic idea of generating gas at the well for operation of the pumping unit has previously been attempted, it has never reached any proportions of commercial success. With the use of a thermostatic control on the extractor, the optimum extraction level for the light hydrocarbons can be controlled, even in varying weather conditions. Also, with the control of outside air drawn into the extractor, the gaseous fuel to air ratio can be adequately controlled to provide reliable long term operation.